Method and system for enhanced resolution in upconverted video using improved interpolation

Abstract

Standard definition video can be upconverted to high-definition video without degrading the appearance of edges, lines and other visual transitions in the image with a diagonal geometry. Each horizontal scan line of the video is monitored to identify the location of such visual transitions. The transitions are then matched in successive scan lines. Successive scan lines are then morphed, e.g., shifted forward or backward to move the transition in each line toward an average position for the transition as located in the two successive scan lines. The successive morphed lines are then added to produce a single interpolated line that is interlaced between its parent lines in a resulting high-definition video signal.

What is claimed is:  
     
       1. A video signal upconversion system, comprising: 
       a detector for detecting visual transitions in a digital video signal;  
       a comparator, connected to said detector, for matching visual transitions in successive scan lines in said digital video signal;  
       variable delay filters controlled by a skew signal from said comparator for delaying or accelerating said digital video signal so as to shift a visual transition in a scan line toward an average location between matched portions of said transition in successive scan lines; and  
       a summing circuit for adding successive scan lines as skewed by said variable delay filters to generate an interpolated scan line.  
     
     
       2. The system of  claim 1 , further comprising a controlled buffer for interlacing scan lines from said video signal with interpolated scan lines output by said summing circuit. 
     
     
       3. The system of  claim 1 , wherein said detector is a luma detector. 
     
     
       4. The system of  claim 1 , wherein said video signal is a color video signal and said variable delay filters shift visual transition in scan lines for each color component of said video signal according to said skew signal. 
     
     
       5. A method of upconverting a video signal, said method comprising: 
       detecting visual transitions in a digital video signal;  
       matching visual transitions in successive scan lines in said digital video signal;  
       delaying or accelerating said digital video signal so as to shift a visual transition in a scan line toward an average location between matched portions of said transition in successive scan lines; and  
       adding successive scan lines as skewed by said delaying or accelerating to generate an interpolated scan line.  
     
     
       6. The method of  claim 5 , further comprising interlacing scan lines from said video signal with interpolated scan lines to generate a high-definition video signal. 
     
     
       7. The method of  claim 6 , wherein said interlacing is performed with a controlled buffer. 
     
     
       8. The method of  claim 5 , wherein said video signal is a color video signal and said method further comprises shifting visual transition in scan lines for each color component of said video signal. 
     
     
       9. The method of  claim 5 , wherein said detecting is performed with a luma detector. 
     
     
       10. The method of  claim 5 , wherein said matching is performed with a line-to-line comparator. 
     
     
       11. The method of  claim 10 , wherein said delaying or accelerating is performed with variable delay filters and said method further comprises controlling said variable delay filters with a skew signal from said line-to-line comparator. 
     
     
       12. A system for upconverting a video signal, said method comprising: 
       means for detecting visual transitions in a digital video signal;  
       means for matching visual transitions in successive scan lines in said digital video signal;  
       means for delaying or accelerating said digital video signal so as to shift a visual transition in a scan line toward an average location between matched portions of said transition in successive scan lines; and  
       means for adding successive scan lines as skewed by said delaying or accelerating to generate an interpolated scan line.  
     
     
       13. The system of  claim 12 , further comprising means for interlacing scan lines from said video signal with interpolated scan lines to generate a high-definition video signal. 
     
     
       14. The system of  claim 13 , wherein said means for interlacing comprise a controlled buffer. 
     
     
       15. The system of  claim 12 , wherein said video signal is a color video signal and said system further comprises means for shifting visual transition in scan lines for each color component of said video signal. 
     
     
       16. The system of  claim 12 , wherein said means for detecting comprise a luma detector. 
     
     
       17. The system of  claim 12 , wherein said means for matching comprises a line-to-line comparator. 
     
     
       18. The system of  claim 17 , wherein said means for delaying or accelerating comprises variable delay filters controlled with a skew signal from said line-to-line comparator. 
     
     
       19. Computer-readable instructions stored on a computer-readable medium, said instructions causing a computer or processor to upconvert a video signal by: 
       detecting visual transitions in said digital video signal;  
       matching visual transitions in successive scan lines in said digital video signal;  
       delaying or accelerating said digital video signal so as to shift a visual transition in a scan line toward an average location between matched portions of said transition in successive scan lines; and  
       adding successive scan lines as skewed by said delaying or accelerating to generate an interpolated scan line.  
     
     
       20. The computer-readable instructions of  claim 19 , further causing said computer or processor to interlace scan lines from said video signal with interpolated scan lines to generate a high-definition video signal. 
     
     
       21. The computer-readable instructions of  claim 19 , wherein said video signal is a color video signal and said instructions further cause said computer or processor to shift visual transitions in scan lines for each color component of said video signal.